Small sunvox to wav converter based upon the example from the library archive

svx2wav.c

//
// * Using SunVox as a filter for some user-generated signal
//   (with export to WAV)
//
  
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dlfcn.h>
#include <signal.h>
#include <math.h>
#include <string.h>
#define SUNVOX_MAIN
#include "sunvox.h"

int g_sv_sampling_rate = 48000; //Hz
int g_sv_channels_num = 2; //1 - mono; 2 - stereo
int g_sv_buffer_size = 1024 * 4; //Audio buffer size (number of frames)
#define POST_GAP 1 //seconds

int keep_running = 1;
void int_handler( int param ) 
{
    keep_running = 0;
}

int main(int argc, char* argv[])
{
    signal( SIGINT, int_handler );
    
    if(argc < 2) {
		printf("Usage: %s <src.sunvox> <dest.wav>\n", argv[0]);
		return 1;
    }
    
    if( sv_load_dll() )
	return 1;
    
    int ver = sv_init( 
		0, 
		g_sv_sampling_rate, 
		g_sv_channels_num, 
		SV_INIT_FLAG_USER_AUDIO_CALLBACK | SV_INIT_FLAG_AUDIO_INT16 | SV_INIT_FLAG_ONE_THREAD
    );
    if( ver >= 0 )
    {
	int major = ( ver >> 16 ) & 255;
	int minor1 = ( ver >> 8 ) & 255;
	int minor2 = ( ver ) & 255;
	printf( "SunVox lib version: %d.%d.%d\n", major, minor1, minor2 );
	
	sv_open_slot( 0 );
	
	if( sv_load( 0, argv[1] ) == 0 )
	    printf( "Loaded.\n" );
	else {
	    printf( "Load error: %s\n", argv[1] );
	    return 1;
	}
	
	const char * title_uns = sv_get_song_name( 0 );
	char * title = malloc(strlen(title_uns)+1);
	int title_len = strlen(title_uns);
	strncpy(title, title_uns, strlen(title_uns));
	for(int i = 0; i < strlen(title); ++i) {
		if(!isprint(title[i])) {
			title[i] = ' ';
			title_len++;
		}
	}
	printf("%s\n", title);
	sv_set_autostop(0, 1);
	

	//Saving the audio stream to the WAV file:
	//(audio format: 16bit stereo interleaved (LRLRLRLR...))
	FILE* f = fopen( argv[2], "wb" );
	if( f )
	{	
	    signed short* buf = (signed short*)malloc( g_sv_buffer_size * g_sv_channels_num * sizeof( signed short ) ); //Output audio buffer
	    signed short* in_buf = (signed short*)malloc( g_sv_buffer_size * g_sv_channels_num * sizeof( signed short ) ); //Input audio buffer
	    unsigned int out_frames = sv_get_song_length_frames(0); 
	    out_frames += g_sv_sampling_rate * POST_GAP; 
        unsigned int out_bytes = out_frames * sizeof( signed short ) * g_sv_channels_num;
      
	    unsigned int cur_frame = 0;
	    unsigned int val;
	    
	    //WAV header:
		fwrite( (void*)"RIFF", 1, 4, f );
		val = 4 + 24 + 8 + out_bytes; fwrite( &val, 4, 1, f );
		fwrite( (void*)"WAVE", 1, 4, f );
		
		//WAV FORMAT:
		fwrite( (void*)"fmt ", 1, 4, f );
		val = 16; fwrite( &val, 4, 1, f );
		val = 1; fwrite( &val, 2, 1, f ); //format
		val = g_sv_channels_num; fwrite( &val, 2, 1, f ); //channels
		val = g_sv_sampling_rate; fwrite( &val, 4, 1, f ); //frames per second
		val = g_sv_sampling_rate * g_sv_channels_num * sizeof( signed short ); fwrite( &val, 4, 1, f ); //bytes per second
		val = g_sv_channels_num * sizeof( signed short ); fwrite( &val, 2, 1, f ); //block align
		val = sizeof( signed short ) * 8; fwrite( &val, 2, 1, f ); //bits
		
		// WAV Title:
		fwrite( (void*)"LIST", 1, 4, f ); // chunk LIST
		val = title_len+12; fwrite( &val, 4, 1, f ); // size of LIST: INFO+INAM+strlen
		fwrite( (void*)"INFO", 1, 4, f ); // subtype INFO
		fwrite( (void*)"INAM", 1, 4, f ); // tag INAM: Title of the subject of the file (name)
		val = title_len; fwrite( &val, 4, 1, f ); // size of text
		fwrite( (void*)title, 1, val, f ); // title text
					
					//*/
					
		//WAV DATA:
		fwrite( (void*)"data", 1, 4, f );
		fwrite( &out_bytes, 4, 1, f );
		int pos = 0;
		
		sv_play_from_beginning(0);
	    while( keep_running && cur_frame < out_frames )
	    {
			int size = g_sv_buffer_size;
			if( cur_frame + size > out_frames )
				size = out_frames - cur_frame;

			//Send it to SunVox and read the filtered output:
			sv_audio_callback2( 
				buf, //output buffer
				size, //output buffer length (frames)
				0, //latency (frames)
				sv_get_ticks(), //output time in system ticks
				0, //input type: 0 - int16; 1 - float32
				g_sv_channels_num, //input channels
				NULL //input buffer
			);
			
			cur_frame += size;
			
			//Save this data to the file:
			fwrite( buf, 1, size * g_sv_channels_num * sizeof( signed short ), f );
			
			//Print some info:
			int new_pos = (int)( ( (float)cur_frame / (float)out_frames ) * 100 );
			if( pos != new_pos )
			{
				printf( "%d %%\n", pos );
				pos = new_pos;
			}
	    }
	    fclose( f );
	    free( buf );
	    free( in_buf );
	}
	else
	{
	    printf( "Can't open the file %s\n", argv[1] );
	}
	
	sv_close_slot( 0 );
	
	sv_deinit();
    }
    else 
    {
	printf( "sv_init() error %d\n", ver );
    }
    
    sv_unload_dll();
    
    return 0;
}